1. Field of the invention
The present invention relates to a fiber stock preparation system for preparing a fiber suspension for use in a paper-making machine, and, more particularly, to an apparatus for discharging a pressurized fluid from a pressurized vessel in such a fiber stock preparation system.
2. Description of the related art
A fiber stock preparation system is used to prepare fiber stock or a fiber suspension which is used in a paper-making machine for the production of a fiber web. To provide a finished fiber web with certain physical characteristics, it is known to load the fibers in the fiber stock with a chemical compound. For example, it is known to load the fibers in a fiber stock with calcium carbonate using a pressurized vessel. For the details of such a fiber loading system, reference is hereby made to U.S. patent application Ser. No. 09/130,176, entitled xe2x80x9cAPPARATUS AND METHOD FOR CHEMICALLY LOADING FIBERS IN A FIBER SUSPENSIONxe2x80x9d, filed Aug. 6, 1998, which is incorporated herein by reference.
In a fiber loading system as described above, the pressurized vessel must be maintained in a pressurized state to effect proper loading of the fibers in the fiber stock. Nonetheless, the pressurized vessel is typically discharged to a transport system such as a conveyor or auger which is in communication with ambient atmospheric pressure. Thus, it is necessary to maintain the interior of the pressurized vessel at a relatively high pressure while at the same time allowing the loaded fiber stock to be discharged to an ambient pressure.
What is needed in the art is an apparatus which maintains a pressurized vessel in a fiber stock preparation system at a higher pressure while allowing the fiber stock to be discharged to ambient pressure.
What is further needed in the art is an apparatus for discharging a pressurized vessel in a fiber stock preparation system which has an adequate flow rate to supply a loaded fiber stock to a paper-making machine, and is simple and relatively inexpensive to manufacture.
The present invention provides a revolver valve with a rotor body disposed within a housing and having a plurality of cylinders which are non-simultaneously disposed in communication with an inlet opening and an outlet opening in an end cap attached to the housing, thereby discharging the pressurized fluid to ambient pressure without substantially decreasing the pressure at the inlet opening.
The invention comprises, in one form thereof, a revolver valve having a housing with a cylindrical inner chamber. A pair of end caps are respectively attached to each end of the housing. One of the end caps includes an inlet opening and the other end cap includes an outlet opening. A cylindrical rotor body is rotatably disposed within the inner chamber of the housing. The rotor body includes a pair of end faces respectively positioned closely adjacent to the end caps, and a plurality of longitudinally extending cylinders extending between the end faces. Each cylinder is positioned generally concentrically about an axis of rotation of the rotor body, whereby the plurality of cylinders are sequentially disposed in communication with the inlet opening and the outlet opening during rotation of the rotor body within the inner chamber during use. The revolver valve is preferably used in a fiber stock preparation system in conjunction with a fiber loading apparatus having a pressurized vessel.
An advantage of the present invention is that a fluid in a pressurized vessel can be discharged to ambient pressure without substantially reducing the higher pressure in the pressurized vessel.
Another advantage is that the pressurized vessel can be discharged at a relatively high flow rate which is sufficient to supply a downstream portion of a fiber stock preparation system.
Yet another advantage is that a portion of the high pressure in a cylinder traveling between the inlet opening and the outlet opening is bled off to an ambient pressure in a cylinder traveling between the outlet opening and the inlet opening to conserve some of the high pressure.
Still another advantage is that a high pressure line is in communication with each cylinder as it travels past the outlet opening, thereby pushing the fluid out the outlet opening and increasing the discharge throughput rate.